An element, a component assembly and also a method of the initially named kind are known from FIGS. 8 and 9 of EP-A-0 539 793. In the method described there the sheet metal part is so designed that it has a conical raised portion in the region of the attachment, with the shaft part of the bolt provided with the thread and also the ring-like rivet section being introduced through a central opening of the conical raised portion coming from the raised side, with the upper region of the conical raised portion being pressed flat during the riveting process and with the rivet bead coming to lie within a ring recess at the underside of the sheet metal part, i.e. at the side of the sheet metal part remote from the head part of the bolt element, with the ring recess still being present even after the partial pressing flat of the conical raised portion.
In the illustrated embodiment a plurality of noses providing security against rotation are present which are distributed uniformly in the peripheral direction, which are present in the region of the transition of the ring recess of the head part into the ring-like rivet section and which have a triangular shape in side view, with the noses providing security against rotation extending in the radial zone only over a part of the width of the ring recess.
Bolt elements of this kind have, however, not been used in practice. One reason for this is that the noses providing security against rotation on the one hand tend, if anything, to hinder the desired reshaping of a sheet metal part and, on the other hand, stiffen the ring-like rivet section whereby the beading over of the beading section proves difficult. Furthermore a design of this kind can lead to undesired deformations of the sheet metal. In this type of element the die button which is responsible for the formation of the rivet bead and for the re-shaping of the sheet metal part presses against the rivet bead and the rivet bead presses against the sheet metal part. Accordingly the rivet bead which is being formed has to press the sheet metal part against the noses providing security against rotation and press the noses providing security against rotation into the sheet material. This proves difficult in practice and it can transpire that the sheet material is caught up at the noses providing security against rotation whereby the formation of the rivet bead fails and the rivet section is deformed and centrally pressed quasi radially into the sheet material.
A series of applications are known in technology in which an element attached to a sheet metal part by riveting is to serve as a centering element. In this connection the element has a part zone of the shaft which fits relatively tightly within a hole of a further component which is attached to the element riveted to the sheet metal part and which is to be accurately positioned relative to the sheet metal part. In this connection the centering element can have a purely centering function, with the screwing on of the further component to the sheet metal part being effected by other elements, or the centering element can simultaneously be provided with a thread which serves for the attachment of the further component to the sheet metal part. The element then has not only a centering function but also an attachment function.
Such centering elements or centering and fastener elements have hitherto been realized by the component Profil Verbindungstechnik GmbH & Co. KG in the form of so-called SBF bolts which are for example described in German patent 3447006.9. In an SBF bolt element the end of the head part remote from the shaft part is designed for a rivet connection with the sheet metal part.
Although such centering elements, optionally with a fastening function, have proved themselves in practice, the attachment to the sheet metal part in the region of the head part of the element requires a relatively large re-shaping of the sheet metal part and of the head part. This leads to a situation in which, for elements with a shaft diameter of 12 mm or more, relatively large re-shaping forces are required in order to achieve the required rivet connection to the sheet metal part. This is in particular problematic when the sheet metal part has a considerable thickness which is frequently the case when using centering elements with a larger shaft diameter.
A similar problem arises also with other fastener elements which can be used for centering purposes.
A further element which can be used as a centering element is described in WO 02/077468. This is a functional element with a head part having a ring-like contact surface and a tubular rivet section standing away from the head part at the side of the contact surface of the head part, with a tubular guide section being disposed concentrically to the tubular rivet section and radially within the latter, with a ring gap being provided between the guide section and the rivet section and with the guide section projecting beyond the free end of the rivet section.
The free end of the wall of the tubular rivet section is rounded both at the radially outer side and also at the radially inner side when seen in an axial section plan and has for example a semicircular shape or a shape resembling an arrow tip which is helpful for the formation of the rivet bead. The guide section is formed as a piercing section and has, at its end remote from the contact surface, a ring-like cutting edge so that the element can be introduced in self-piercing form into a sheet metal part. The element is formed as a nut element which first makes the self-piercing function possible. In this element no ring recess is however provided in the ring-like contact surface and the noses providing security against rotation have the shape of raised portions or ribs which extend in the radial direction and which are formed at the ring-like contact surface.